From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0A90C43612 for ; Thu, 10 Jan 2019 12:28:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9D3A21773 for ; Thu, 10 Jan 2019 12:28:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727865AbfAJM17 (ORCPT ); Thu, 10 Jan 2019 07:27:59 -0500 Received: from guitar.tcltek.co.il ([192.115.133.116]:52784 "EHLO mx.tkos.co.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727391AbfAJM17 (ORCPT ); Thu, 10 Jan 2019 07:27:59 -0500 Received: from tarshish.tkos.co.il (unknown [10.0.8.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx.tkos.co.il (Postfix) with ESMTPS id 806E544087E; Thu, 10 Jan 2019 14:27:55 +0200 (IST) From: Baruch Siach To: Linus Walleij , Bartosz Golaszewski , Thierry Reding , Thomas Petazzoni , Lorenzo Pieralisi , Bjorn Helgaas Cc: Sven Auhagen , linux-pwm@vger.kernel.org, linux-gpio@vger.kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jason Cooper , Andrew Lunn , Gregory Clement , Sebastian Hesselbarth , Baruch Siach Subject: [PATCH 2/2] PCI: armada8k: don't toggle reset twice Date: Thu, 10 Jan 2019 14:26:22 +0200 Message-Id: <94cd23a60c647020dd87a923684b59255b89f02c.1547123182.git.baruch@tkos.co.il> X-Mailer: git-send-email 2.20.1 In-Reply-To: <024cc24efa7b99186750f90c91880b29357d379d.1547123182.git.baruch@tkos.co.il> References: <024cc24efa7b99186750f90c91880b29357d379d.1547123182.git.baruch@tkos.co.il> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Commit 3d71746c42 ("PCI: armada8k: Add support for gpio controlled reset signal") added reset signal support. Reset is unconditionally asserted and deasserted. Unfortunately, that commit breaks boot on Macchiatobin when a Mellanox NIC is in the PCIe slot. It turns out that you can toggle the reset signal only once. Another reset signal toggle makes access to PCI configuration registers stall indefinitely. U-Boot toggles the Macchiatobin PCIe reset line already at boot. Detect whether the bootloader changed the reset signal state using the get_direction operation. If direction is output don't touch the reset signal again. Otherwise, set direction to output and keep the reset asserted. Reported-by: Sven Auhagen Signed-off-by: Baruch Siach --- This patch depends on the mvebu get_direction implementation in the patch #1 of this series. Since get_direction implementation is not a pure fix it might be considered unfit for v5.0. In that case I'm OK with reverting 3d71746c42 in v5.0 to fix the Macchiatobin regression, and postpone this series to v5.1. --- drivers/pci/controller/dwc/pcie-armada8k.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-armada8k.c b/drivers/pci/controller/dwc/pcie-armada8k.c index b171b6bc15c8..132a86a1e1e7 100644 --- a/drivers/pci/controller/dwc/pcie-armada8k.c +++ b/drivers/pci/controller/dwc/pcie-armada8k.c @@ -257,12 +257,23 @@ static int armada8k_pcie_probe(struct platform_device *pdev) goto fail_clkreg; } - /* Get reset gpio signal and hold asserted (logically high) */ + /* Get reset gpio signal, don't change its setting */ pcie->reset_gpio = devm_gpiod_get_optional(dev, "reset", - GPIOD_OUT_HIGH); + GPIOD_ASIS); if (IS_ERR(pcie->reset_gpio)) { ret = PTR_ERR(pcie->reset_gpio); goto fail_clkreg; + } else if (pcie->reset_gpio && + gpiod_get_direction(pcie->reset_gpio) == 0) { + /* Reset signal is output. The bootloader has deasserted reset + * signal already. Don't do it again. + */ + dev_info(dev, "%s: leave reset signal unchanged\n", __func__); + devm_gpiod_put(dev, pcie->reset_gpio); + pcie->reset_gpio = NULL; + } else if (pcie->reset_gpio) { + /* Assert reset */ + gpiod_direction_output(pcie->reset_gpio, 1); } platform_set_drvdata(pdev, pcie); -- 2.20.1